September weather forecastTønsberg, Norway

September

Weather in September

In Tønsberg, September is synonymous with the beginning of the fall season, witnessing a significant drop in temperature and daylight hours. Temperatures settle around 15.3°C (59.5°F) on average, marking the onset of cooler weather. As the month advances, rainfall continues to be highly frequent, but the city sees a reduction in sunshine hours. However, this month's beauty lies in witnessing the transition from summer to fall, amid changing foliage and crisp air.

Temperature

September in Tønsberg, Norway, is characterized by a mild reduction in the average high-temperature, from an enjoyable 18.4°C (65.1°F) in August to a still refreshing 15.3°C (59.5°F). Tønsberg's nighttime temperature in September experiences a slight dip from daytime highs, falling to an average of 10.8°C (51.4°F).

Humidity

In Tønsberg, the average relative humidity in September is 77%.

Rainfall

In Tønsberg, during September, the rain falls for 11.1 days and regularly aggregates up to 55mm (2.17") of precipitation. Throughout the year, in Tønsberg, there are 130.2 rainfall days, and 549mm (21.61") of precipitation is accumulated.

Snowfall

In Tønsberg, Norway, snow does not fall in May through September.

Sea temperature

In Tønsberg, in September, the average water temperature is 15.8°C (60.4°F).
Note: Swimming in 15.8°C (60.4°F) is not a pleasurable activity for the majority of people. Breathing becomes increasingly challenging as water temperature descends from 21°C (69.8°F) to 15°C (59°F).

Daylight

The average length of the day in September is 12h and 50min.
On the first day of the month, sunrise is at 06:16 and sunset at 20:19. On the last day of September, in Tønsberg, sunrise is at 07:22 and sunset at 18:54 CEST.

Sunshine

In September, the average sunshine in Tønsberg is 8.3h.

UV index

In September, the average daily maximum UV index in Tønsberg is 3. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for average individuals.
Note: The maximum UV index of 3 during September leads to these instructions:
Undertake protective steps - Preventing sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.

Updated: Jan 26, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Tønsberg in September has an average high-temperature of 15.3°C (59.5°F) and an average low-temperature of 10.8°C (51.4°F).

In September, the average relative humidity is 77%.

In Tønsberg, in September, it is raining for 11.1 days, with typically 55mm (2.17") of accumulated precipitation.

In Tønsberg, snow does not fall in May through September.

In Tønsberg, Norway, in September, it doesn't snow. In October, it regularly snows.

In September, the average sea temperature in Tønsberg is 15.8°C (60.4°F). Swimming in 15.8°C (60.4°F) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 21°C (69.8°F).

In September, the average day length is 12h and 50min.

On the first day of September in Tønsberg, Norway, sunrise is at 06:16 and sunset at 20:19. On the last day of the month, sunrise is at 07:22 and sunset at 18:54 CEST.

In Tønsberg, Norway, the average sunshine duration in September is 8.3h.

In September, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a medium hazard to health from exposure to the Sun's UV radiation.

Today

Tomorrow

Long-term

Year J F M A M J J A September O N D

Aug

September

Oct

Average high temperature

18.4°C

15.3°C

9.8°C

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

15.7km/h

17.4km/h

19km/h

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

0.5

Average sea temperature

Average daylight

Average sunshine

Average sunshine days

14.8

17.3

17.2

Average UV index

Average cloud cover

Average visibility

Average temperature in September
Tønsberg, Norway

Average high temperature in September: 15.3°C

The warmest month (with the highest average high temperature) is July (19.1°C).
The month with the lowest average high temperature is February (0.3°C).

Average low temperature in September: 10.8°C

The month with the highest average low temperature is July (13.7°C).
The coldest month (with the lowest average low temperature) is February (-3°C).

Average pressure in September
Tønsberg, Norway

Average pressure in September: 1012.8mbar

The month with the highest atmospheric pressure is April (1014.4mbar).
The month with the lowest atmospheric pressure is December (1008mbar).

Average wind speed in September
Tønsberg, Norway

Average wind speed in September: 16.7km/h

The windiest months (with the highest average wind speed) are November and December (19.7km/h).
The calmest month (with the lowest average wind speed) is July (13.9km/h).

Average humidity in September
Tønsberg, Norway

Average humidity in September: 77%

The month with the highest relative humidity is February (85%).
The months with the lowest relative humidity are April and May (72%).

Average rainfall in September
Tønsberg, Norway

Average rainfall in September: 55mm

The wettest month (with the highest rainfall) is November (65mm).
The driest month (with the least rainfall) is April (23mm).

Average rainfall days in September
Tønsberg, Norway

Average rainfall days in September: 11.1 days

The month with the highest number of rainy days is July (15.2 days).
The month with the least rainy days is February (5.9 days).

Average snowfall in September
Tønsberg, Norway

Average snowfall in September: 0mm

The month with the highest snowfall is January (111mm).
The months with the least snowfall are May, June, July, August and September (0mm).

Average snowfall days in September
Tønsberg, Norway

Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (9.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average sea temperature in September
Tønsberg, Norway

Average sea temperature in September: 15.8°C

The best month for swimming (with the highest average sea temperature) is August (18.4°C).
The coldest month (with the lowest average sea temperature) is March (2.8°C).

Average daylight in September /
Average sunshine in September
Tønsberg, Norway

Average daylight in September: 12h and 48min

The month with the longest days is June (Average daylight: 18h and 30min).
The month with the shortest days is December (Average daylight: 6h and 18min).

Average sunshine in September: 8h and 18min

The month with the most sunshine is June (Average sunshine: 11h and 36min).
The month with the least sunshine is December (Average sunshine: 3h and 24min).

Average sunshine days in September
Tønsberg, Norway

Average sunshine days in September: 17.3 days

The month with the most sunshine days is April (19.9 days).
The months with the least sunshine days are June and July (13.4 days).

Average UV index in September
Tønsberg, Norway

Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average cloud cover in September
Tønsberg, Norway

Average cloud cover in September: 41

The month with the most cloud cover is February (Cloud cover 59).
The months with the least cloud cover are June, July and August (Cloud cover 36).

Average visibility in September
Tønsberg, Norway

Average visibility in September: 10km

The months with the highest visibility are April, May, June, July, August, September and October (10km).
The months with the lowest visibility are January, February, March, November and December (9km).